1866440 has 32 divisors (see below), whose sum is σ = 4347000. Its totient is φ = 720384.

The previous prime is 1866439. The next prime is 1866451. The reversal of 1866440 is 446681.

It can be written as a sum of positive squares in 4 ways, for example, as 1833316 + 33124 = 1354^2 + 182^2 .

It is a super-3 number, since 3×1866440³ = 19505781485333952000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 356 + ... + 1964.

2^1866440 is an apocalyptic number.

1866440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1866440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2173500).

1866440 is an abundant number, since it is smaller than the sum of its proper divisors (2480560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1866440 is a wasteful number, since it uses less digits than its factorization.

1866440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1649 (or 1645 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 1866440 is about 1366.1771481034. The cubic root of 1866440 is about 123.1226660899.

The spelling of 1866440 in words is "one million, eight hundred sixty-six thousand, four hundred forty".